This invention relates to an apparatus for the processing and scrubbing of contaminated gases i.e., gas entrained with particulate matter. More particularly, this invention relates to an apparatus comprising a primary dust removal unit which receives a descending gas pipeline originating from a generator or source of contaminated gases. This primary dust removal unit acts to precipitate the larger solid particles from the contaminated gas via gravity and/or inertia to form semi-scrubbed gas. A plurality of scrubbers are provided within the primary dust removal unit to effect the forced scrubbing of the semi-scrubbed gases from the primary unit. Each of these scrubbers contain a series of bag filters which are traversed from bottom to top by the semi-scrubbed gases. The scrubbers also include means for monitoring the temperature of the gases at different points in their passage and means for cooling or heating the gases in order to maintain their temperature within predetermined operational limits.
While not being limited thereto in its utility, the description herein will refer to an apparatus for the processing and scrubbing of contaminated gases which is associated with a high furnace. It should be understood that the crude gases produced in such a high furnace are discharged therefrom at variable and relatively high temperatures and pressures as compared to the ambient atmosphere; and are also laden or entrained with dusts and other solid particulate matter. It will be appreciated that the apparatus of the present invention is also suitable for use in conjunction with any other source of contaminated gases having solid particles entrained therein.
It is well known that contaminated gases, such as those obtained from a high furnace, contain combustible components therein. Accordingly, such contaminated gases are well suited for use as a heating gas. However, before these contaminated gases may be practically used in a distribution network as a heating gas, they must be cooled, reduced in pressure, cleaned and scrubbed. These processing operations are usually performed in a gas processing installation which incorporates a primary dust removal unit (generally known as a "dust bag"); which may possibly be associated with a cyclone. These gas processing installations usually further include a forced scrubbing unit which consists of a damp washer; the damp washer being responsible for the cooling and decompression of the gases.
Although such gas processing has enabled the reusable components of the contaminated gases to be recovered (in the form of a heating gas), such prior art processing installations include may deficiencies with regard to the recovery of accumulated energy in the combustible gases in the form of heat and pressure. This loss of energy (loss of inherent heat and pressure) is due in part, to the damp washing which can not be carried out without the dissipation of a large portion of the energy inherent in the contaminated gases.
As energy conservation and energy efficiency has gained increasingly greater importance in manufacturing processing, a scrubbing technique has recently been provided which acts to preclude the above discussed loss of inherent heat and pressure and thereby enable a large portion of the energy in the contaminated gases to be recovered despite the scrubbing and other gas processing steps. This new energy efficient gas processing technique is described in German Patent Document No. DE-Al-3,129,812 wherein a process is disclosed for replacing the damp washing by a final scrubbing. This final scrubbing is performed dry and does not involve simultaneous dissipation of the heat and pressure as in the prior art damp washing process. In other words, in the process disclosed in the German Patent Document, the final scrubbing phase has been separated from the decompression and cooling phase, so that the energy derived from the decompression and cooling phases may be efficiently utilized. Accordingly, the process described in the German Patent document attempts to provide a maximum recovery of the energy available within gases emitted from a contaminated gas source.
While suitable for its intended purposes, the gas processing apparatus described in the above discussed German Patent Document for carrying out this energy efficient scrubbing process nevertheless has a number of disadvantages and deficiencies which are discussed in greater detail hereinbelow.